Hospitalized lithium overdose cases reported to the California Poison Control System.

BACKGROUND: Lithium overdose primarily results in neurologic toxicity; however, cardiac effects have also been reported. Our aim was to describe a large cohort of hospitalized lithium overdose patients. Specifically we were interested in reported cardiac complications, frequency of hemodialysis (HD), and mortality. METHODS: This is a retrospective, observational case series of admitted isolated lithium exposure cases reported to the California Poison Control System (CPCS) from 2003 through 2007. Reported lithium exposure cases were identified by a search of our CPCS database. Only those cases resulting in hospital admission were included in this study. Cases with concomitant toxic exposures were excluded. Primary outcome variables were reported cardiac complications (defined as bradycardia with a heart rate < or =50 bpm, atrioventricular (AV) block, ventricular tachycardia, and ventricular fibrillation), administration of cardiovascular intervention (resuscitation, vasopressor medications, or cardiac pacing), and death. RESULTS: In the 5-year-study period 629 lithium cases were reported to the CPCS and 502 hospitalized cases were included in this study. There were 44 [8.8%; 95% confidence intervals (CI) 6.3, 11.2] cases of acute lithium exposure, 124 (24.7%; 95% CI 20.9, 28.5) cases of acute on chronic (AC) overdose, and 282 (56.2%; 95% CI 51.8, 60.5) cases of chronic overdose. Sixty-nine patients received hemodialysis. This includes 6 (13.6%) acute, 12 (9.7%) AC, and 45 (16.0%) chronic cases. There were four deaths (0.8%, 95% CI 0.2, 1.6). Cardiac complications were reported in 29 cases (5.7%, 95% CI 3.7, 7.7%) with 18 of these cases (18/29; 62%) being isolated bradycardias (without hypotension). Only seven patients with reported cardiac complication (7/29; 24.1%; 95% CI = 8.6, 39.7) required cardiovascular intervention and all of these were cases of chronic lithium toxicity. Two bradycardic arrests occurred in chronic lithium exposure cases, including one who died. CONCLUSION: In this cohort of hospitalized lithium exposure patients, death was rare. Reported cardiac complications were unusual with instances requiring cardiovascular intervention occurring only in cases of chronic lithium overdose. The majority of lithium toxicity cases were managed without HD.

Tramadol exposures reported to statewide poison control system.

BACKGROUND: Tramadol is a unique analgesic that has been associated with seizures on overdose. OBJECTIVE: To determine the toxic effects associated with tramadol exposure. METHODS: A retrospective chart review of tramadol exposures reported to a multisite, state-wide poison control system over a 2.5-year period was performed. RESULTS: A total of 602 cases were retrieved; 190 had sufficient data for study evaluation. Cases with coingestants or unknown outcomes were eliminated. Of the 190 remaining cases, 55% were females. Acute ingestions represented 90.0%, chronic ingestions 7.9%, and acute on chronic 2.1% of the overdoses. Ages of the patients ranged from 9 months to 80 years. Suicide attempts represented the largest group of exposures. Main symptoms included central nervous system (CNS) depression (27.4%), nausea and vomiting (21.1%), tachycardia (17.4%), and seizures (13.7%). Dosage ranged from a taste amount to 5000 mg. The smallest amount of tramadol associated with seizure was 200 mg, and 84.6% of seizures occurred within 6 hours of time of ingestion. Logistic regression analysis showed an association between seizures and tramadol use in males, chronic use, suicide attempts, intentional abuse or misuse, and tachycardia (HR >100 beats/min). No effect was seen in 36.3% of patients, minor effects in 43.7%, moderate effects in 19.5%, and major effects in 0.5%. Symptoms resolved within 24 hours in 96.7% of the 121 patients who had symptoms. Naloxone improved CNS depression in 7 of 8 patients in whom a response was documented. CONCLUSIONS: Tramadol overdoses frequently cause CNS depression, nausea/vomiting, tachycardia, and seizures. Symptoms generally resolve within 24 hours. Accidental ingestions in children were well tolerated, primarily causing sedation.